Rapidly melting ice in the Far North alarms climatologists and lures nations into competition for newly accessible trade routes and resources.

On August 2, a pair of 18-ton Russian submersibles, Mir-I and Mir-II, plunged more than two miles down into the Arctic Ocean and planted a titanium capsule containing their nation’s flag on the seabed at the North Pole. Russian parliamentarian and explorer Artur Chilingarov, who rode in the first of the two minisubmarines to reach the ocean floor, declared, “Our task is to remind the world that Russia is a great Arctic and scientific power,” to which Canadian foreign minister Peter MacKay retorted: “This isn’t the 15th century. You can’t go around the world and just plant flags and say, ‘We’re claiming this territory.’”

The posturing is part of a deadly serious race. As the melting of the Arctic sea ice accelerates, countries with claims on Arctic Circle territory—including not just Russia and Canada but also the United States, Denmark, Norway, Sweden, Iceland, and Finland—are scrambling to send mapping expeditions to the icy North. Within days of the twin Mir descent, the U.S. Coast Guard had dispatched the icebreaker Healy north of Alaska to spend nearly a month mapping the Arctic Ocean’s floor; Canada commenced a 10-day military exercise called a “sovereignty operation”; and the Danes sent scientists to map the seabed north of Greenland. The prizes are not just the much-vaunted oil and gas reserves that lie beneath the Arctic but also access to the Northwest Passage, a shipping route between the West and Asia across the Arctic that year-round ice packs have long made impassable. If the Northwest Passage were to open, the route from London to Tokyo would be 3,000 miles shorter than the one through the Suez Canal.

In September, a scientific expedition was under way on a two-and-a-half-month voyage in the North Polar Sea. The research vessel Polarstern was carrying 50 scientists from 10 nations, including the United States, Germany, Russia, China, and Japan. In addition to measuring currents, temperatures, and seawater salinity, the scientists calculated sea ice thickness with the aid of a torpedo-shaped instrument, towed by a helicopter, that beamed electromagnetic waves at the ice surface. With this “EM Bird,” the team discovered that large tracts of Arctic sea ice are now only three feet deep—half the thickness of a mere six years ago.

The ice cover is drastically shrinking as well. On September 14, the European Space Agency announced that satellite images captured earlier in the month by the Advanced Synthetic Aperture Radar instrument aboard its Envisat satellite showed that the Arctic sea ice had dwindled to its smallest size since measurement began 30 years ago. According to remote-sensing specialist Leif Toudal Pedersen of the Danish National Space Center, the area covered by ice in the Arctic has shrunk to just 1.15 million square miles, about 386,000 square miles less than previous minimums reached in 2005 and 2006. In contrast, average ice loss in each year of the past decade had been about 38,600 square miles.

If the Northwest Passage were to open, the route from London to Tokyo would be 3,000 miles shorter than the one through the Suez Canal.

In Greenland, the melting ice has triggered a diamond rush and pulled in companies keen to exploit other rich mineral deposits like zinc and gold. But the biggest prize is black gold. Estimates of untapped oil resources in the Arctic range from about 3 percent of the world’s undiscovered reserves to the probably hyperinflated figure of 25 percent. A survey published in 2006 by energy consultants Wood Mackenzie found only about one quarter of the oil previously estimated to lie under the Arctic; they also noted that as much as 85 percent of the remaining reserves are in the form of gas, which is hard to transport. Still, the firm predicts the Arctic could deliver as many as 3 million barrels of oil equivalent per day.

That could be one reason Russia, Denmark, and Canada are tussling over the Lomonosov Ridge, an underwater formation rising 10,500 feet above the Arctic seabed. All three countries claim that the ridge is part of their continental shelf, which would give them rights to exploit the Arctic Ocean’s natural resources.

Climatologists and glaciologists like Ted Scambos of the National Snow and Ice Data Center are alarmed. Scambos points out that the melting of the Arctic ice fuels a strong feedback loop that will accelerate global warming. “There truly is a catastrophe brewing in the Arctic,” Scambos says. The ice sheet reflects energy into space, and as that bright reflective surface is lost, more heat is trapped in the ocean. “As you lose the sea ice, you uncap the ocean, and there’s a lot of heat and humidity from the ocean that’s exchanged with the atmosphere,” he explains. “We can anticipate that there will be very large and more rapid changes in the areas surrounding the Arctic Ocean, but more generally throughout the Northern Hemisphere. It’s going to feel as though someone stepped on the gas pedal in terms of global warming,” he says, concluding ruefully, “in the next one to two decades, we’ll have little or no Arctic sea ice in late summer.”